much less

English

(idiomatic) Let alone; to say nothing of, not to mention.
Synonym: never mind

You wouldn't want a dog running around the house, much less a monkey!
- 1927-29, M.K. Gandhi, The Story of My Experiments with Truth, translated 1940 by Mahadev Desai, Part I, Chapter xxi:
  Of the thing that sustains him through trials man has no inkling, much less knowledge, at the time.
- 1919, Parker Hoysted Fillmore, The Three Citrons:
  Why, not even a little bird or a tiny butterfly comes here, much less a human being!
- 1895. M.K. Gandhi, Petition to Natal Legislative Assembly
  It is hopeless for him to return to India and expect to earn bread, much less to make a fortune.
- 1886, Ulysses S. Grant, Personal Memoirs of U. S. Grant:
  We had not at Chattanooga animals to pull a single piece of artillery, much less a supply train.
Used other than figuratively or idiomatically: see much,‎ less.
He's at the bar much less often than his mother lately.

The idiomatic construction follows this form:

"not [a small thing], much less [a bigger thing]" – "She was so poor that she had not a single coin, much less the large amount demanded."
"not [to do a small thing], much less [to do a bigger thing]." – "He has broken his ankle. He can not even walk, much less run and jump".

let alone